DENVER, CO. – JANUARY 21: Sandy Gold of Denver pumps gas at a gas station at Holly and Florida with their gas price down to $2.73 January 21, 2013. Sandy Gold has a Pet Sitting Company and likes the lowering gas prices. The average cost of a gallon of gasoline is $2.75 in the metro area.

Prices in Denver on Sunday were 36.3 cents a gallon lower than the same day one year ago and are 7.7 cents a gallon lower than a month ago.

The national average for a gallon of gasoline on Sunday was $3.49, having fallen 1.6 cents in the past week, according to GasBuddy.

The national average has decreased 13.3 cents a gallon in the last month and stands 32.2 cents a gallon lower than this day a year ago.

Patrick DeHaan, senior petroleum analyst for GasBuddy.com, said that the lower prices Colorado and the nation have been experiencing may be over.

“We’ve seen situations unfold that have caused a reversal in the downward trend, and those situations are multiplying across portions of the United States and Canada,” said DeHaan.

“Along the West Coast, supply has grown tight and will lead to likely increases. In the Great Lakes, prices may spike 10 to 20 cents a gallon in the next two days in over a half dozen states as a result of a similar situation,” said DeHaan.

DeHaan said refineries are finishing what was an extensive maintenance season. With the plants starting up again, “problems may develop, putting pressure on prices,” he said.

GasBuddy operates DenverGasPrices.com and more than 250 similar websites that track gasoline prices at more than 140,000 gasoline stations in the United States and Canada.

As news of the deadly mass shooting at Marjory Stoneman Douglas High School in Parkland, Florida, unfolded last week, Pia Guerra, a 46-year-old Vancouver-based artist, felt helpless. She couldn’t bring herself to go to sleep, so she began to draw.

Police who find suspected drugs during a traffic stop or an arrest usually pause to perform a simple task: They place some of the material in a vial filled with liquid. If the liquid turns a certain color, it’s supposed to confirm the presence of cocaine, heroin or other narcotics.